1. Field of the Invention
The invention relates to a steering system.
2. Description of Related Art
A steering column described in US Patent Application Publication No. 2009-0013817 (US 2009/0013817 A) includes an adjustment portion that positions the steering column and a holding portion that does not move in a direction in which the position of the steering column is adjusted (adjustment direction). The holding portion is provided with tooth portions arranged in the adjustment direction. A tooth plate of an elastomer is inserted through a clamp bolt penetrating the adjustment portion and the holding portion. The tooth plate has tooth portions arranged in the adjustment direction.
Operating an operation member attached to the clamp bolt allows a pressing member through which the clamp bolt is inserted to be moved toward the holding portion. Moving the pressing member toward the holding portion causes the tooth plate to be pressed by the pressing member to move toward the holding portion. At this time, the tooth portions of the tooth plate are each placed between the tooth portions of the holding portion to engage the tooth portions of the holding portion with the tooth portions of the tooth plate.
The steering column described in US 2009/0013817 A needs to operate the operation member with a predetermined force (operating force) during locking. When the operation member is locked, unlike the case where the tooth portions of the tooth plate mesh properly with the tooth portions of the holding portion, when the tooth portions of the tooth plate fail to mesh properly with the tooth portions of the holding portion and move onto the tooth portions of the holding portion to deflect the tooth plate, the reaction force of the deflected tooth plate acts on the operation member via the pressing member to increase the operating force. Thus, the operating force exerted on the operating member may vary between the case of the proper meshing between the tooth portions of the tooth plate and the tooth portions of the holding portion and the case of the failure in the proper meshing, which leads to an unstable operating force.